Activation of wood for dyeing with a



FIPQ-EUJ xx 2.0539119 kn? MM I ,5 I by Jan. 31, 1956 H. R. NACK 2,733,119 ACTIVATION 0F WOOD FOR DYEING WITH A BASIC DYESTUFF if) Filed Nov. 6, 1951 UNSTAINED WOOD TREAT WITH AGENT REACTIVE WITH WOOD RINSE EXCESS AGENT FROM WOOD SAN D TREAT WOOD WITH DYE SOLUTION INVENTOR HERMAN R. NAGK ATTORNEYS Patented Jan. 31, 1956 ACTIVATION. or wool) non DYEING A nxsrc nvns'rurr Herman R. Nack, Troy, Ohio, assignor to Chadeloid Corporation, Dayton, Ohio, a corporation of Delaware Application November 6, 1951, Serial No. 255,102

1 Claim; (Cl. 8--6.5)

This invention relates to a method of staining wood.

It is a primary object of the invention to provide a method for the staining of woods which is effective to highlight contrasting effects present in the natural wood. This objective is attained through reduction of the effect of knots, gum spots, grain formations, and so forth.

A further object of the invention is the provision of a method for the staining of woods which results in more uniform distribution of the staining dye, and a higher and more penetrating dye deposit than has hitherto been attainable. f

These and other allied objectives of the invention are attained by providing a treatment for the unstained wood, which treatment conditions the surface of the wood for receipt of the staining dye. Thus in the process of invention the unstained wood is first subjected to the action of an agent capable of changing the reactive nature of the wood surface and the surface is then treatedwith a dye having reactive characteristics such that it will be attracted and bound to the wood. 5

More specifically the process involves treating unstained wood such as mahogany, poplar or walnut, with an agent which acidifies or oxidizes the wood, or? with an agent which creates a basicity or reduction ."Qf the wood surface, and thereafter contacting the treated gwood with a dye having basic or acidic properties in the-opposite sense. That is, an acidified wood surface wonld be treated with a dye having basic properties andv'ice versa.

As acidic and/or oxidizing constituents sodium hypochlorite water solutions, or a 0.5% nitric acid splution may be utilized. The concentration of the hypo'cli when such is employed may vary from about 1% t" by weight.

The base or reducing agents may include 3 hydrosulphide or stannous chloride and the concert} "ation in water may preferably be in the range of Between about 1 to 15% by weight.

Dyes suitable in conjunction with the oxidizing or. acid treatment include particularly Brilliant Green Crystals, Color index No. 662; Fuchsine GS, Color index 677; these dyes are adaptable especially where high penetration of the wood is required although it will be understood that others of the same characteristics indicated may be utilized and the invention is not to be considered as limited to a particular dye.

Similarly preferred acidic dyes include Calcocid Fast Light Orange 2 G, Color index 27, and Calcocid Yellow MXXX Conc, Color index 138.

The concentrations of the dyes, which are employed in solution form, may vary between about V2% to 7% depending upon the particular dye desired to be produced. With the acid dyestuffs the preferred solvent is Carbitol the ethyl ether of diethylene glycol while the basic dyestuffs may be employed in ethyl alcohol, or Cello-solve, the monoethyl' ether of ethylene glycol. Solvent selection is not critical and those solvents customarily effective with particular dyestuffs may beutilized in the inventive process.

The invention will be more fully understood by reference to the accompanying flow sheet and the following detailed examples:

Example I Unstained walnut is first subjected to a water solution containing 10% sodium hypochlorite by weight for about ten minutes, the treated wood is then rinsed in methanol, dried and. lightly sanded to a smooth surface. The clean dry wood is then sprayed with a 4% solution of Brilliant Green Crystals in alcohol and dried.

The resultant product will be more strongly and effectively stained, with a greater degree of uniformity than a similar wood sample produced without the preliminary hypochlorite treatment.

Example I! A poplar wood panel may be subjected to the action of a 5% solution of sodium hypochlorite for about 15 minutes, and after rinsing with methanol, drying and sanding, sprayed with a 3% solution of Fuchsine CS, CI 677 in the ethyl ether of diethylene glycol.

The resultant panel will be superior in coloration to panels treated with higher dye concentrations but which were not given the initial hypochlorite treatment.

Example III A walnut panel may be treated with a 5% solution of sodium hydrosulphide in water for about 10 minutes, then rinsed, dried and sanded. A 3% solution of an acid dyestuif, Calcocid Yellow MXXX Conc. CI 138 may then be sprayed onto the clean wood and thereafter dried. The product will exhibit improved quality, particularly as to the depth, over a panel not subjected to the hydrosulphide step. More uniform staining permitting ease of matching will also be attained in the product.

Example IV A mahogany panel may be subjected to an 8% solution of stannous chloride in water for about 15 minutes, then rinsed with alcohol, dried and sanded. A spray of a solution containing about 7% Calcocid Fast Light Orange 2 G, Color index 27, may then be directed onto the panel. The panel when dried will exhibit a deep coloration with improved fading properties over a panel prepared without the initial treatment.

In connection with the stannous chloride solution in water it may be noted that this solution preferably should be freshly prepared in order to minimize any premature oxidative tendency to the stannic ion.

Acidification of the stannous solution should in general be avoided, for though the same normally tends to prevent hydrolysis of the stannous, if freshly prepared this factor will be overcome and the adverse effect of acid on the wood, where undesirable, will not be encountered.

It will be understood that while there have been given herein certain specific examples of the practice of this invention, it is not intended thereby to have this invention limited to or circumscribed by the specific details of materials, proportions, or conditions herein specified, in view of the fact that this invention may be modified according to individual preference or conditions without necessarily departing from the spirit of this disclosure and the scope of the appended claim.

I claim;

A process of staining walnut wood which comprises the steps of (a)applying to the surface of the unstained wood a water solution containing 10% by weight of sodium hypochlorite and retaining said solution in contact with the wood for approximately ten minutes, (b) rinsing the wood with methanol, (c) lightly sanding the rinsed surface of the wood, and (d) applying thereover a dye solu-- -3 4 tion containing Brilliant Green Crystals to dye the wood 1,792,805 Broderick Feb. 17, 1931 and thereafter drying'the same. 1,876,329 Loetscher Sept. 6, 1932 References Cited in the file of this patent OTHER REFERENCES UNITED STATES PATENTS 5 Textile Colorist for June 1937, pp. 25, 26 (article by Rice). 755,993 Brenner Mar. 29, 1904 

